#include"myStdio.h"
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<stdlib.h>
#include<unistd.h>
#include<assert.h>

#define FILE_MODE 0666

_FILE *_fopen(const char *filename,const char *flag)
{
    assert(filename);
    assert(flag);

    int f = 0;
    int fd = -1;

    if(strcmp(flag, "w") == 0)
    {
        f = (O_CREAT|O_WRONLY|O_TRUNC);
        fd = open(filename, f, FILE_MODE); 
    }
    else if(strcmp(flag, "a") == 0)
    {
        f = O_RDONLY;
        fd = open(filename, f);
    }
    else
    {
        return NULL;
    }

    if(fd == -1) return NULL;

    _FILE *fp = (_FILE*)malloc(sizeof(_FILE));
    if(fp == NULL) return NULL; 

    fp->fileno = fd;
    fp->out_pos = 0;
    return fp;

}

int _fwrite(_FILE *fp, const char *s, int len)
{
    memcpy(&fp->outbuffer[fp->out_pos], s, len);
    fp->out_pos += len;

    if(fp->flag & FLUSH_NOW)
    {
        write(fp->fileno, fp->outbuffer, fp->out_pos);
        fp->out_pos = 0;
    }
    else if(fp->flag & FLUSH_LINE) 
    {

        if(fp->outbuffer[fp->out_pos - 1] == '\n')
        {
            write(fp->fileno, fp->outbuffer, fp->out_pos);
            fp->out_pos = 0;
        }
    }
    
    return len; 
}

void _fflush(_FILE *fp)
{
    if(fp->out_pos > 0)
    {
        write(fp->fileno, fp->outbuffer, fp->out_pos);
        fp->out_pos = 0;
    }
}

void _fclose(_FILE *fp)
{
    if(fp == NULL) return ;
    _fflush(fp);
    close(fp->fileno);
    free(fp);
}
